The LSi 25's on ebay for $1300 are factory refurbs with a warranty sold on Polk's ebay store so the amps are probably going to be O.K. for a while. They used to have the 15's for $849/pr which was a real nice deal.
I have a pair of well traveled 25's and the whole speaker, including the amps, are doing just fine. I don't crank mine up so I can't say how they would work for your application but if you like the 9's then the 25's should have a very similar sound. But for music the LSi's almost require a dead quiet room to get the most out of that tweeter so I wouldn't try and use them as a "frat house" speaker. But who knows. Maybe they'd do just fine. Probably better options out there though like the JBL's. Or maybe even the old RTi12's? Reasonable on CL.
I certainly agree 25's are more then most people need and the 15's (or even 9's) are all most would need but my main complaint with the 25's is they're just too darn tall (49 inches). But they do very well with two channel music in Pure Analog if you prefer a slightly darker mid-range and softer tweeter (meaning the opposite of bright) like I do. But like I said, I need the room to be whisper quiet.
I think I like the old LSi's a little bit better (not so much the LSi 7's though) then most around here, and elsewhere, and I'm going to miss them if they ever sell. I'd love to try the new LSiM's but they're just too much $$$, even the few that pop up on the used market.